Xcode 11: How to stack editor vertically?

Question

I like to have 3 Editor windows, 1 Main window and the other half of the screen is split vertically with 2 windows. I use to be able to do this easily in Xcode 10 and earlier, but looks like I cant in Xcode 11. Anyone figure this out?

Answer 1

Firstly the default behaviour:

If you click the new window icon at the top right then you get a new window to the right of the current one.

Now for adding a window vertically:

If you hold down the Alt Key then the icon changes to and then if you click it you will get a new window below the current one.

(Note that if you already have vertically stacked windows the icons default is a vertical split and then pressing Alt reverts it to a horizontal one instead.)